最新的研究表明，有些中风发作后患者，特别是老年人尽管没有相应的临床表现如失语、偏瘫或大小便障碍等，但仍可损害老年人脑功能如记忆力降低。上述所谓的无相关临床表现的中风常常被称之为无症状性中风（silent strokes），在老年人中的发病率经磁共振扫描检查约为25％。因此，有必要加强无症状性中风之识别和防治。更多资讯，请参阅全文。

'Silent Strokes' Linked to Memory Loss in Elderly: Study

More memory woes noted in seniors who had experienced these events, researchers say.

THURSDAY, Dec. 29 (HealthDay News) -- In some cases, memory loss among the elderly may be due to so-called "silent strokes," new research suggests.

Such strokes, which may not cause any noticeable symptoms, result in small pockets of dead brain cells, and are found in roughly 25 percent of older adults, the study team noted.

"The new aspect of this study of memory loss in the elderly is that it examines silent strokes and [brain] shrinkage simultaneously," study author Adam Brickman, of the Taub Institute for Research on Alzheimer's Disease and the Aging Brain at Columbia University Medical Center in New York, explained in a news release from the American Academy of Neurology.

The research, which was funded by the U.S. National Institutes of Health, is slated for publication in the Jan. 3 issue of the journal Neurology.

The study authors arrived at their conclusions after working with 658 men and women aged 65 and older, none of whom had a history of dementia.

All the participants underwent MRI brain scans, as well as testing to gauge their capacities in terms of memory, language skills, thinking speed and visual perception.

The brain scans revealed that 174 of the participants had experienced silent strokes, and the investigators found that these seniors did not perform as well on the memory exams. This finding held regardless of whether the part of the patient's brain responsible for memory (the hippocampus) was found to be relatively small or not.

"Given that conditions like Alzheimer's disease are defined mainly by memory problems, our results may lead to further insight into what causes symptoms and the development of new interventions for prevention," Brickman noted in the news release. 　"Since silent strokes and the volume of the hippocampus appeared to be associated with memory loss separately in our study, our results also support stroke prevention as a means for staving off memory problems," he added.

SOURCE: American Academy of Neurology, news release, Dec. 28, 2011